I expect if you reached out to Caleb or Ken at GA Precision, they should be able to quickly look up the build sheet on that specific rifle and tell you the specs. I just sent back a couple of my previous builds to them for some work and was uncertain the specs on one of them, which Caleb was able to pull up the build sheet while we talked to confirm. Since the freebore is something that has changed a couple times, and could have even ordered up outside the norm if someone was neck turning brass.
This a cool ass rifle, have one very similar that GAP spun up for me in 2018 that shoots lights out. Love the Vias camo stock and cerekote combo on this rifle, and expect it would prove a lot more marketable here if you knew the bore specs. Good luck with the sale.